In use of catheters for introduction into a body cavity, a process called catheterization, it is common in some instances to include on the catheter itself an inflatable balloon or "cuff" which is inflated after introduction of the catheter to prevent accidental retraction or rejection of the catheter. It is usual to inflate the cuff from an outside source of air as, for example, a bulb pump. Representative of the prior art in this field is a U.S. Pat. No. 4,573,966 to Weikl et al.
The present invention is directed to a self-inflating cuff which can be used when the catheter is utilized for perfusion of liquid into a body cavity. One known means of accomplishing this inflation is to provide the catheter with an inflatable cuff surrounding the outside of the catheter spaced from the distal end. Openings into the cuff from the lumen are provided spaced axially of the lumen, and the sides of distal end of the catheter are provided with a plurality of openings for outflow of the perfusion liquid. The end of the lumen within the cuff is closed off and the openings are designed such that there will be a pressure in the lumen which will exert on the interior of the cuff to cause inflation.
It is an object of the invention to provide an improved self-inflating cuff which reduces stagnation of inflating media in the cuff and reduces the pressure drop across the cuff. It is a further object to provide an optional axial vent which prevents stagnation in the body of the catheter under the cuff. A further object is to provide a reinforcement to prevent unintentional collapse of the catheter in the cuff area. Pressure monitoring is important in the use of a perfusion function and an object is also to allow monitoring of the cuff pressure as well as the vessel pressure.
Pressure that approximates the intra-vessel condition in normal operation will also register cuff pressure. However, should the pressure monitor show an increase as might occur if the distal end of the catheter is inadvertently occluded, this would indicate undue pressure in the cuff and require immediate attention of the monitoring personnel. Other objects include a lumen plug with a design to assist in introducing the distal end of the catheter into a vessel.
Other objects and features of the invention will be apparent in the following description and claims in which the invention is described together with details to enable persons skilled in the art to practice the invention, all in connection with the best mode presently contemplated for the invention.